Many products such as fruits, vegetables and fermented tobacco products have biological activity after harvesting and preparation for market. This activity can be described as a respiration process where there is a biological process consuming oxygen from the ambient environment and energy sources inherent in the product and producing carbon dioxide and water as a by product. By packaging these products in an impermeable package, the oxygen will be consumed and moisture produced. As the oxygen is consumed, the process may transition to an anaerobic process and continue, by producing by-products that further degrade the product. Combined with an affinity of some products to be in a narrow humidity range for optimum storage conditions, it is apparent that prolonged storage is a delicate balance of conditions. This is further complicated by variation in optimum conditions for different product types.
Conventionally, membranes can be adhered to the package (e.g. with adhesives or other sealing means) in an attempt to solve the above-discussed problem. However, the sealing of the membrane is a secondary process that is done to the packaging material for the final package, and thus, there is a potential pathway through the seal, which is not controlled. This could result in something other than the designed conditions being present, which may not be known to the user.